A palletizer is an apparatus that receives and manipulates items, such as boxes, and places the manipulated articles on pallets in pre-determined positions and orientations in organized rows, layers and stacks to form a stable stack of boxes arranged on a pallet for shipping. There are innumerable devices for palletizing articles, but described in a very general sense all palletizers receive a sequence of items and manipulate those items to produce a palletized stack of them. Typically, a completed stack of cartons is shrink wrapped as part of the palletizing operation in order to finalize the stack for shipping.
Stated in very general terms, a typical palletizer receives a series of items, organizes the items into rows, organizes the rows into layers, and generates a stack of layers on a pallet.
Efficient shipping of palletized items calls for efficient stacking of items on the pallet to minimize open space within the stack and to help insure the stability of the stack to prevent relative movement between items, and ultimately, to insure that the items in the stack arrive at their destination undamaged. Of course, boxes come in a variety of sizes and many boxes are rectangular with opposed parallel side panels and therefore have different width and length dimensions. A standard pallet is used widely throughout the shipping industry. By varying the orientation and/or pattern of boxes from layer to layer, a stable stack of items may be constructed upon a standard-sized pallet. Accordingly, a variety of “box patterns” have been established for stacking specific box sizes on standard pallets. By using an established box pattern for given rectangular boxes that are to be stacked on a standard pallet, the result is an efficient and stable stack of the boxes on the pallet that will perform well during shipping and handling.
A common palletizing system comprises several components that work together to perform the palletizing operation. Boxes are initially placed on an infeed system that delivers the boxes to a row build system. Often the infeed system includes box turning equipment that orients individual boxes in the correct orientation relative to adjacent boxes for the specific box pattern that is being used. Rows are assembled on the row build system—each row is a set of plural boxes arranged according to the box pattern. A row is transferred by one of a variety of methods from the row build system to a layer building station where plural rows are arranged into a layer. A stack is formed by depositing a first layer onto a pallet or slip sheet and subsequent layers are deposited atop the next adjacent lower layer. Layers are added until the stack is complete. Typically, the palletizing operations at the various stations run simultaneously to the extent possible to increase throughput efficiency. As would be expected, there are many variations of the equipment used to palletize, and the general themes of operation.
Regardless of the equipment that is being used, palletizing requires efficiency in design and operation of the device. Among other design and operational criteria, efficiency is often one of the most important considerations. In many applications, time is most critical and a palletizer that more quickly organizes an incoming series of items into a palletized stack of items represents an advantage by increasing throughput and thus greater production levels and economic efficiency.
It will be appreciated that mishandling of boxes in the palletizing process should be minimized as part of an efficient operation and that a palletizing system must be designed to avoid delivery of boxes to the palletizer in an incorrect orientation. For example, a box that is delivered to a palletizer in the incorrect orientation for the specific box pattern that is being used will cause formation of a defective layer. This results in shut down, or at least significant slowdown of the entire palletizing sequence and operator intervention is often required in order to correct the orientation of the mis-oriented box. Unfortunately, delivery of such “out of bounds” boxes—that is, boxes that are either in the incorrect orientation or which are otherwise improperly placed—to palletizing systems continues to be a significant problem and is the cause of much slowdown in palletizing operations. Moreover, any time operator intervention is required to correct out of bounds situations presents a safety concern for workers.
There is a need therefore for a palletizing system that insures delivery of boxes to the equipment in the correct orientation and spacing for whatever box pattern is being used.
The present invention comprises systems that address the shortcomings of prior systems.